Dance Anatomy & Kinesiology

The Upper Extremity 405

Shoulder Extension

In open kinematic chain movements, shoulder exten-
sion often involves moving the arm backward and
downward from a position of flexion (such as from
high fifth to low fifth) in approximately the sagittal
plane. However, when the torso is upright, gravity
will tend to produce this movement, and shoulder
extension is primarily controlled with eccentric con-
traction of the shoulder flexors and scapular upward
rotators. However, if the arm is brought beyond
anatomical position (hyperextension), where the
motion is now against gravity (as seen with the right
arm in figure 7.27), or if the motion is opposed by
another external resistance such as a wall pulley,
elastic tubing, or springs (e.g., sitting row [table
7.10D, p. 435] or triceps kick back [table 7.10, E
and O, pp. 436 and 444]), the shoulder extensors—
including the posterior deltoid, latissimus dorsi,
and teres major—would be used concentrically to
produce the desired extension, accompanied by
relative scapular adduction, and downward rotation
(rhomboids, levator scapulae, and lower trapezius
to neutralize undesired elevation). Similarly, with
a pull-up (closed kinematic chain), extension
would occur against gravity (e.g., lifting the body
up against gravity), and the shoulder extensors
(including the pectoralis major [sternal], latissimus
dorsi, and teres major) would work concentrically
on the up-phase to produce this shoulder extension.
Here, this hanging position would tend to produce
extreme elevation of the scapulae, and forceful and
deliberate scapular depression (lower trapezius,
serratus anterior) would ideally accompany shoulder
extension.

Shoulder Abduction

When the hand is free to move (open kinematic
chain), shoulder abduction refers to moving the
arm sideways away from the midline of the body
in approximately the frontal plane, as in raising
the arms to the side from low fifth to high fifth,
jumping jacks, or the side arm raise (table 7.10F,

p. 437) performed with a weight. In dance, one or

both arms are often held in a position of about 90°

abduction to facilitate balance or achieve aesthetic

goals (as seen with the left arm in figure 7.28). The

shoulder abductors—particularly the supraspinatus

and deltoid—would be used to effect these motions.

When the shoulder is externally rotated, the biceps

brachii can also aid with shoulder abduction (Smith,

Weiss, and Lehmkuhl, 1996). When the arms are

raised above shoulder height, the clavicular por-

tion of the pectoralis major can also assist with

abduction (table 7.4). Shoulder abduction (greater

FIGURE 7.27 Sample dance movement showing

shoulder extension.

Shoulder movement Primary muscles Secondary muscles

Horizontal abduction Middle deltoid

Posterior deltoid

Infraspinatus

Teres minor

Latissimus dorsi

Teres major

Horizontal adduction Anterior deltoid

Pectoralis major

Biceps brachii (short head)

Coracobrachialis

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